Approximately 75,000-150,000 patients each year in the United States are identified as suffering from chest pain of unknown etiology (CP). These patients have excessive levels of disability and account for $250,000,000- $500,000,000 in estimated health care costs each year. There are no standard treatment protocols that have been shown to reliably improve these patients' pain and disability and to reduce their excessive health care utilization, although there is some evidence that regimens of imipramine and cognitive-behavioral therapy may produce short-term reductions in pain intensity. We propose to perform the first 16-week randomized controlled outcome study of these interventions in which 160 CP patients will be assigned to one of four treatment conditions: cognitive- behavioral therapy (CBT), attention-placebo social support intervention, pharmacologic (imipramine) therapy, or pharmacologic placebo. Assessments will be performed at baseline, post-treatment, 6-month follow-up, and 12- month follow-up to evaluate the short and long term efficacy of the interventions. Dependent variables will consist primarily of measures that we have found to distinguish CP patients from patients with other painful gastrointestinal disorders and from healthy controls: clinical pain intensity, pain thresholds and response bias for esophageal balloon distension, coping strategies, self-efficacy, and spouse response to patients pain behavior. Health care utilization and disability also will be assessed to evaluate changes in patients' quality of life. We will test 7 specific hypotheses involving comparisons of CBT and pharmacologic therapy in improving pain and quality of life among CP patients. This study also will be unique in- that it will determine whether one or both of our experimental treatments influence the factors that underlie altered pain perception and symptom reports among CP patients (i.e., pain threshold and response bias levels). Finally, this is the first outcome study of treatments for patients with CP that will evaluate whether patients maintain their improvements for 12 months following treatment and that will evaluate clinical, as well as statistical significance of treatment effects.